1. Field of the Invention
This invention relates to a mold for molding plastic bottles.
2. Description of the Prior Art
Molding plastic bottles has been conventionally carried out such that parison is first supplied into the cavity between two molds facing to each other during opening the molds, and then they are clamped when parison is fully supplied by a predetermined length, next the parison is pressed against the wall with compressed air inside the parison in the molds, and finally they are opened after curing the molding material.
The cavity-forming-wall is formed coarsely with the intention of no remaining of the air between the parison and the wall during blowing compressed air into the parison.
However, in the conventional mold, the outside surface of a molding formed by the blow of compressed air and the expansion of the parison itself produces a pome-like ground or lowness in luster because of the roughness of the wall surface. On the other hand, a smooth surface of the wall for enhancing the luster causes remaining of the air between the parison and the wall at the time of contact of the parison expanded by compressed air with the wall. And accordingly the external surface of the molding produces uneavenness, which materially reduces the value as merchandise.